METHOD FOR STARTING A MOTOR VEHICLE ENGINE AND ENGINE CONTROL UNIT FOR CONTROLLING A MOTOR VEHICLE ENGINE

• US 20160215719A1
• Filed: 01/20/2016
• Published: 07/28/2016
• Est. Priority Date: 01/23/2015
• Status: Active Grant

• Current Assignee: Dr Ing hc F Porsche AG (Volkswagen AG)
• Original Assignee: Dr Ing hc F Porsche AG (Volkswagen AG)
• Inventors: Nawrocik, Michal, Baisch, Philipp, Gross, Heiko, Grau, Alexander
• Granted Patent: US 10,082,096 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: F02D 2200/101 Engine speed
• CPC Class Codes: F02D 2200/1012 Engine speed gradient
• CPC Class Codes: F02D 2250/28 Control for reducing torsional vibrations, e.g. at acceleration
• CPC Class Codes: F02D 41/062 for starting F02D41/061 takes precedence
• CPC Class Codes: F02D 41/22 Safety or indicating devices for abnormal conditions in air/fuel ratio feedback systems F02D41/1495, in electric control linkage F02D11/107, in purge control systems F02M25/0809
• CPC Class Codes: F02D 41/34 with means for controlling injection timing or duration
• CPC Class Codes: F02P 5/1506 with particular means during starting
• CPC Class Codes: Y02T 10/40 Engine management systems

Abstract

A method for starting a motor vehicle engine includes measuring the profile of a rotational speed of an engine shaft of the motor vehicle engine. An estimated rotation speed of the engine shaft is determined that is expected to be present after one working cycle of the next cylinder to be fired. The estimated rotational speed is compared with a resonant rotational speed range of a vibration damper. Where the vibration damper is configured as a dual-mass flywheel and resonant vibrations occur in the vibration damper within the resonant rotational speed range. If the estimated rotational speed is within the resonant rotational speed range, at least one of introduction parameters for the introduction of a fluid to be introduced into the cylinder or an ignition time of the cylinder is changed so as to change the estimated rotational speed to be outside the resonant rotational speed range.

Claims

1. :

A method for starting a motor vehicle engine, comprising;

measuring the profile of a rotational speed of an engine shaft of the motor vehicle engine,

determining an estimated rotation speed of the engine shaft that is expected to be present after one working cycle in a cylinder of the motor vehicle engine that is the next to be fired,

comparing the estimated rotational speed with a resonant rotational speed range of a vibration damper, the vibration damper being configured as a dual-mass flywheel, wherein resonant vibrations occur in the vibration damper within the resonant rotational speed range, and

if the estimated rotational speed is within the resonant rotational speed range, changing at least one of introduction parameters for the introduction of a fluid to be introduced into the cylinder or an ignition time of the cylinder so as to change the estimated rotational speed to be outside the resonant rotational speed range.

2. :

The method as recited in claim 1, wherein the fluid to be introduced is a fuel or a fuel/air mixture, and

wherein the introduction of the fluid is by at least one of induction or injection.

3. :

The method as recited in claim 1, wherein the determination of the estimated rotational speed and the changing of the introduction parameters and/or of the ignition time, which take place if necessary, occur after the last working cycle of the cylinder.

4. :

The method as recited in claim 3, wherein the determination of the estimated rotational speed and the changing of the introduction parameters and/or of the ignition time, which take place if necessary, occur after the expulsion cycle.

5. :

The method as recited in claim 1, wherein the determination of the estimated rotational speed occurs by extrapolation of the rotational speed profile, wherein, in particular, at least one time period of the rotational speed profile which comprises the last four cycles of the cylinder is taken into account for the extrapolation of the rotational speed profile.

6. :

The method as recited in claim 1, wherein when the introduction parameters are changed, at least one of an introduction starting time, an introduction end time, an introduction period, an introduction quantity of the introduction fluid or a composition of the introduction fluid which is to be introduced is changed.

7. :

The method as recited in claim 1, wherein at least two different cylinders of the motor vehicle engine are examined.

8. :

The method as recited in claim 1, wherein a starting signal for starting the motor vehicle engine is detected, and subsequently the cylinder which is to be fired first of all is determined, wherein the cylinder which is to be fired first of all is examined first.

9. :

The method as recited in claim 1, wherein the method is ended after a predefined maximum number of cycle passes of the cylinder and/or a predefined maximum number of examined cylinders.

10. :

The method as recited in claim 1, wherein the method is started only after a starting signal for starting the motor vehicle engine has been detected.

11. :

An engine control unit for controlling a motor vehicle engine, comprising;

a measuring device for measuring the profile of a rotational speed of an engine shaft of the motor vehicle engine;

a computing unit for determining an estimated rotational speed of the engine shaft which is expected to be present after one working cycle in a cylinder of the motor vehicle engine which is the next to be fired;

a comparator unit for comparing the estimated rotational speed with a resonant rotational speed range of a vibration damper configured as a dual-mass flywheel, wherein resonant vibrations in the vibration damper occur within the resonant rotational speed range; and

a control unit for changing at least one of introduction parameters for the introduction of a fluid to be introduced into the cylinder or an ignition time of the cylinder so as to change the estimated rotational speed to be outside the resonant rotational speed.

12. :

A motor vehicle engine for driving a motor vehicle, comprising;

an engine shaft for conducting out a torque;

at least one cylinder for generating the torque by burning an introduced fluid; and

an engine control unit for influencing at least one of the introduction parameters or the ignition time for each of the at least one cylinder as a function of a rotational speed profile of the engine shaft, the engine control unit including;

a measuring device for measuring the profile of a rotational speed of an engine shaft of the motor vehicle engine;

a computing unit for determining an estimated rotational speed of the engine shaft which is expected to be present after one working cycle in a cylinder of the motor vehicle engine which is the next to be fired;

a comparator unit for comparing the estimated rotational speed with a resonant rotational speed range of a vibration damper configured as a dual-mass flywheel, wherein resonant vibrations in the vibration damper occur within the resonant rotational speed range; and

a control unit for changing at least one of introduction parameters for the introduction of a fluid to be introduced into the cylinder or an ignition time of the cylinder so as to change the estimated rotational speed to be outside the resonant rotational speed.

13. :

The motor vehicle engine as recited in claim 12, wherein the at least one cylinder includes four cylinders.